IRA_SETEQ

Encodes the epoch of a reference equinox within an SCS name

Description:

On entry, SCS contains the name of a Sky Co-ordinate System (or an unambiguous abbreviation), with or without an equinox specifier (see routine IRA_ISCS). On exit, SCS contains the full name of the Sky Co-ordinate System with an equinox specifier appended, determined by arguments EQU and BJ. Any old equinox specifier is first removed. If the Sky Co-ordinate System is not referred to the equinox (e.g. GALACTIC) then no equinox specifier is included in SCS on exit.

Invocation

CALL IRA_SETEQ( EQU, BJ, SCS, STATUS )

Arguments

EQU = DOUBLE PRECISION (Given)
The epoch of the reference equinox. After calling this routine, the sky co-ordinates described by SCS are referred to the mean equinox of the epoch given by EQU. If EQU has the Starlink " BAD" value (VAL__BADD) then no equinox specifier is included in SCS on exit.
BJ = CHARACTER ∗ ( ∗ ) (Given)
Determines if the epoch specified by argument EQU is a Besselian or Julian epoch. BJ should have the value " B" or " J" . Any other value causes an error report (except that a blank value causes " B" to be used if EQU is less than 1984.0 and " J" otherwise).
SCS = CHARACTER ∗ ( ∗ ) (Given and Returned)
On entry, SCS should contain an unambiguous abbreviation of a supported Sky Co-ordinate System (see routine IRA_ISCS), with or without an equinox specifier. On exit, SCS contains the full name of the Sky Co-ordinate System, appended with an equinox specifier determined by arguments EQU and BJ. If the Sky Co-ordinate System is not one that is referred to the equinox (e.g. GALACTIC) then no equinox specifier is included in SCS on exit. SCS should have a declared length equal to the symbolic constant IRA__SZSCS.
STATUS = INTEGER (Given and Returned)
The global status.